The present invention relates to an arrangement for regenerating a soot burn-off filter in the exhaust duct of an air-compressing fuel-injected internal combustion engine.
As is known, soot burn-off filters have only a limited regenerative capacity and, particularly when an internal combustion engine is operated at low load and speed, accumulate soot particles which burn off only at higher temperatures as a result of higher loads and speeds. However, a minimum oxygen content in the exhaust gas is also required for regeneration; and increasing exhaust-gas backpressure impairs the gas exchange of the internal combustion engine so that the oxygen content in the exhaust gas is decreased in the case of full-load operation at a constant injection quantity. The result is an undesireably low regeneration of the soot burn-off filter.
This disadvantage has been remedied by an arrangement disclosed in German Patent Document DE 36 02 038 C1, in which a servomechanism reduces the injection quantity metered to the internal combustion engine as a function of increasing exhaust-gas backpressure in the exhaust duct. The servomechanism is provided with a spring-loaded diaphragm which can be subjected to the exhaust-gas backpressure and, and which has a diaphragm rod operatively connected to the governor linkage of a speed governor.
It is an object of the present invention, in an internal combustion engine already having an adjustment device which influences the injection quantity, to provide apparatus which requires little construction expenditure, which avoids impairment of the functioning of the arrangement that can be subjected to the exhaust-gas backpressure, and which effects the regeneration of the soot burn-off filter.
This and other objects and advantages are achieved by the regeneration arrangement according to the invention, in which due to a special structurally unitary combination of the regenerating arrangement with the altitude-matching device, only a low expenditure on construction is required. The exhaust-gas backpressure acting on the diaphragm thus acts via the altitude-matching device on the governor linkage of the speed governor and correspondingly compensates the injection quantity to be metered to the internal combustion engine.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.